How to fix error 3002 upgrading to iOS5 (Mac/Windows)
UPDATE: As I'm sure you can tell, the Apple servers are having some major issues right now because of the amount of traffic they are receiving. If you can't upgrade or restore and you have tried the fix below, just keep trying, you will ge through eventually.
A few of our readers have been reporting receiving an unknown error(3002) when trying to update to iOS5. This appears to indicate that you are blocking Apple's verification servers in your hosts file much like the 1015 errors we have seen in the past. There is a very simple fix for this.
Step 1. Navigate to C:\Windows\System32\Drivers\etc
Step 3. Find this line in your hosts file and delete it(delete any entries):
Step 4. Now save your hosts file with the gs.apple.com lines removed.
Step 5. Launch iTunes and hit restore and or update and you should get to iOS5 no problem.
Step 1. Open Terminal, then type the following in order to open your hosts file:
sudo nano /etc/hosts
Step 2. Find this line in your hosts file and delete it:
Step 3. Save your hosts file.
Step 4. Launch iTunes and hit restore and or update and you should get to iOS5 no problem.
Other users have been experiencing a different error "An internal error occured (3200)." This error seems to be because Apple's servers are getting swamped from all the traffic. Wait for a while and then try restoring/updating again.